<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<script type="text/javascript" src="../shiro/manager/jquery-1.10.2.min.js"></script>
</head>
<body>
	<span class="intro">love</span>
	<span class="demo">this</span>
	<span class="intro demo">game</span>
</body>

<script type="text/javascript">
var elements = $(".intro"); // 所有class=intro而且class=demo的元素
elements.css("background-color", "gray");
</script>
</html>